1. Field of the Invention
The present invention relates to a refuse incinerator for burning mainly refuse and more particularly to a small refuse incinerator capable of extinguishing smoke and odor accompanying combustion of refuse.
2. Description of the Related Art
Conventionally, a technology for burning exhaust gas secondarily with an after-burner in order to extinguish smoke and odor of that exhaust gas generated when refuse is burnt has been known. For example, according to Japanese Patent Application Laid-Open No.HEI7-225015, a secondary combustion burner is disposed in a secondary combustion chamber provided adjacent a primary combustion chamber and the exhaust gas generated in the primary combustion chamber is burnt completely with the secondary combustion burner so as to extinguish its smoke.
Further, another technology for extinguishing smoke by secondary heating with far infrared ray from a far infrared ray irradiation material disposed within an incinerator has been also known. For example, according to Japanese Patent Application Laid-Open No.HEI7-324719, a net cylinder is disposed within the combustion chamber of a furnace and a far infrared ray irradiation material is loaded between the net cylinder and an inner wall of the combustion chamber. In this furnace, refuse is burnt within the net cylinder and generated exhaust gas passes through far infrared ray irradiation material layers and rises, so that the exhaust gas is burnt completely and discharged into the air.
However, the refuse incinerator described in the former publication requires the secondary combustion chamber and the secondary combustion burner and consequently, the size thereof is increased and its combustion cost rises. Thus, this refuse incinerator is unsuitable for a small refuse incinerator. In case of the refuse incinerator described in the latter publication, because a stack is provided just above the combustion chamber, exhaust gas passes upward quickly and is discharged out without being subjected to sufficient irradiation of the far infrared ray, so that the exhaust gas is not burnt completely, thereby leaving smoke.
To solve such a problem, as shown in FIG. 9, a refuse incinerator 101 disclosed in Japanese Patent Publication No.2001-141216 (U.S. Pat. No. 6,325,000B1), comprises a furnace main body 102, a combustion chamber 105 disposed below the furnace main body 102, a heat insulation wall 103 having a first far infrared ray irradiation body disposed so as to surround the furnace main body 102 and the combustion chamber 105, a heat exchanger 104 disposed so as to surround the heat exchanger 103, an inner smoke path 107 formed between the heat insulation wall 103 and the furnace main body 102, an outer smoke path 109 formed between the heat insulation wall 103 and the heat exchanger 104 and communicating with the inner smoke path 107, a heat insulation member 110, which is a second far infrared ray irradiation body disposed above a connecting portion 108 between the inner smoke path 107 and the outer smoke path 109 and exhaust gas outlets 106 disposed in the furnace main body 102 such that it faces the connecting portion 108.
Therefore, in the refuse incinerator 101, as indicated with a dot and dash line in FIG. 9, exhaust gas is discharged into the connecting portion 108 from the exhaust gas outlets 106 and then, heated by the far infrared ray irradiated from the heat insulation wall 103 and the heat insulation material 110 in the connecting portion 108 and high temperature combustion gas from the combustion chamber 105. Further, because a top portion of the connecting portion 108 is closed so that down draft of air is formed, heat is unlikely to escape. For the reason, exhaust gas is heated to high temperatures, so that the smoke and odor are dissolved and extinguished. Additionally, because no secondary burner is required, the size of the refuse incinerator can be reduced.
However, although exhaust gas is discharged directly into the connecting portion 108 in the refuse incinerator 101, the temperature of the connecting portion 108 is not raised sufficiently in a while just after the incineration of the refuse is started, because the connecting portion 108 is located far from the combustion chamber 105. Consequently, the exhaust gas is not heated to a sufficiently high temperature and therefore, there is such a fear that the smoke and odor of the exhaust gas cannot be extinguished.
The present invention intends to solve the above-described problem and therefore provides a refuse incinerator capable of extinguishing smoke and odor of exhaust gas generated from incineration of refuse just after the incineration of the refuse is started.
To achieve the above object, according to an aspect of the present invention, there is provided a refuse incinerator comprising: an incineration furnace containing a furnace main body and a furnace lid which is put on the furnace main body; a combustion chamber provided below the furnace main body; a heat insulation wall provided so as to surround the furnace main body and the combustion chamber; a heat exchanger provided so as to surround the heat insulation wall; an exhaust gas chamber whose bottom wall contains at least a part of the furnace lid; an exhaust gas outlet provided in a portion of the incineration furnace, the portion facing the exhaust gas chamber; an exhaust gas introduction pipe communicating between the exhaust gas chamber and the combustion chamber; a first smoke path formed between the furnace main body and the heat insulation wall and whose bottom portion is connected to the combustion chamber; and a second smoke path formed between the heat insulation wall and the heat exchanger and whose top portion is connected to the top portion of the first smoke path.
According to another aspect of the present invention, the refuse incinerator may further comprise a box body including a top wall portion provided with a door body which can be opened/closed and a peripheral wall portion, the incineration furnace being accommodated within the box body, the heat exchanger being provided within the box body, the exhaust gas chamber being formed at a top portion within the box body, the refuse incinerator further comprising a third smoke path, formed between the heat exchanger and the peripheral wall portion and whose bottom portion is connected to the bottom portion of the second smoke path and having a discharge port.
Preferably, the exhaust gas outlet is provided on the furnace lid.
Further preferably, the refuse incinerator further comprises an air supply unit and an air supply pipe connected to the air supply unit, wherein a front end portion of the air supply pipe is inserted into the exhaust gas introduction pipe and an air spouting port which is an outlet of the air supply pipe is disposed within the exhaust gas introduction pipe such that it faces an exhaust gas combustion chamber outlet which is an outlet of the exhaust gas introduction pipe.
Still further preferably, the refuse incinerator further comprises an air spouting pipe connected to the air supply unit, wherein an ash discharge port is provided in the bottom portion of the furnace main body and the front end portion of the air spouting pipe passes through the ash discharge port and is projected into the-furnace main body.